This application proposes to improve treatment outcomes for methamphetamine- (MA-) dependent subjects through development of an innovative cognitive behavioral therapy- (CBT-) based text messaging intervention. While CBT reduces MA use, it and other psychosocial therapies have limited effectiveness, and patients treated for MA dependence have a high rate of relapse. Thus, a significant need exists for add-on therapy for treatment of MA dependence. We are using an iterative process to develop and refine this intervention. We have convened an expert panel, conducted three focus groups with MA-dependent subjects, interviewed 25 subjects being treated for MA dependence, and conducted a five-subject feasibility trial. We will reconvene the expert panel to review our candidate text messages and study methods. Active and control text messages will be uploaded into a web-based application that we have developed for this purpose. We will conduct a pre-test in which 10 subjects receive two weeks of the active text messages and two weeks of control text messages; these conditions will be in random, counterbalanced order with a one-week washout. Messages will be pushed to subjects four times per day and can also be pulled on an as-requested basis. Subjects will attend one-hour CBT-based group therapy sessions three times per week. We will collect urine samples for toxicological analyses, self-reports of MA use, craving scores, and ratings of the utility and acceptability of the intervention Qualitative interviews after subjects complete each condition will assess the perceived utility of the approach, preferences for message content, and acceptability. When all subjects have completed, we will hold a focus group and reconvene the expert panel. After making any indicated revisions to the text messages or procedures, we will implement a second crossover trial with 40 subjects, conduct another focus group with subjects who were in the second trial, reconvene the expert panel again, and select text messages to be used in a subsequent large randomized parallel group trial. This will be an inexpensive intervention to deploy that utilizes technology that is affordable and widely available - basic cellular telephones. The low-intensity, high-frequency, and always available characteristics of this intervention contrast to conventional outpatient treatment and may be a valuable complement to it. It will be readily extensible, both to MA users who cannot attend formal treatment, and also to individuals dependent on other drugs.